As analyzers become larger and larger to handle more and more tests per hour, it becomes necessary to have more than one incubator to receive sample-bearing slide test elements to incubate them, for higher through-put. See, for example, U.S. Pat. No. 4,512,952, FIG. 1, by D. L. Blanding et al. However, the more incubators that are required, the larger the "foot-print" of the analyzer. Compare, e.g., the footprint of a three-incubator analyzer of the '952 patent, with the footprint of a two-incubator analyzer as shown in U.S. Pat. No. 4,296,070.
The through-put of said '952 patent analyzer is roughly about 700 test elements per hour. To expand this to 1,000 or more places even greater burdens on the analyzer, such as larger or more numerous incubators. Hence, the foot-print tends to become larger still. Larger foot-prints are unacceptable in crowded laboratories.
Thus, there has been a problem in increasing the through-put of the analyzer above, say, 700 slide elements per hour, without drastically increasing the foot-print.
In a related, commonly-owned application cofiled herewith by James Miller, entitled Twin Roter Incubator Assembly U.S. application Ser. No. 08/235,041, a solution to that problem is provided by stacking one incubator generally above the other. However, once that is done, there remains the problem of loading slide elements into those stacked incubators. The traditional mechanism for loading the incubators of the '952 and the '070 patents is to use a rotating slide distributor. To do this at two different levels would require the slide distributor to have a vertical motion as well as a rotary motion. Because of the size of the slide distributor and its mass, such additional degree of freedom in its motion is not deemed to be practical.
Thus, the problem addressed by this invention is to allow the use of vertically-stacked incubators without also requiring the rotating slide distributor to move up and down as well, to the levels of the stacked incubators.